On-chip inductors are receiving attention as semiconductor devices become increasingly compact. Inductors are particularly difficult to miniaturize due to the principles of electromagnetic fields on which they depend. Furthermore, semiconductor devices employing inductors are being designed to operate over increasingly high frequencies and broad bandwidths, yet also employ increasingly miniaturized components and system-on-a-chip architectures.
Prior approaches often fail to operate satisfactory under these parameters. One such approach is the co-location of a patterned magnetic film near a fixed value inductor. This approach helps to miniaturize the fixed value inductor by influencing the electromagnetic field that surrounds the inductor when operating. However, this approach fails to permit a sufficient degree of miniaturization for many system-on-a-chip applications.
Furthermore, such inductors are of fixed value. The use of fixed value inductors limits the operational frequency and bandwidth ranges of the parent device. In devices that operate at multiple frequencies or across wide bandwidths, it can be advantageous to use inductors of variable value. Thus, there is a need for an integrated inductor which is actively tunable and more highly miniaturizable.